Lindblad Expeditions specializes in environmentally sensitive, soft-adventure vacations that are explorative and informal in nature -- what the company calls "respectful tourism." Its programs -- operated since 2004 in partnership with the National Geographic Society -- are designed to appeal to the intellectually curious traveler seeking a cruise that's ecologically friendly and educational, as well as being relaxing. Days aboard are spent learning about life above and below the sea (from National Geographic experts to high-caliber expedition leaders trained in botany, anthropology, biology, and geology), and observing the world either from the ship or during shore excursions, which are included in the cruise package. Educational films and slide presentations aboard ship precede nature hikes and quick jaunts aboard Zodiac boats. Flexibility and spontaneity are keys to the experience, as the route may be altered at any time to follow a pod of whales or school of dolphins.

The Alaska program of its two ships, the nearly identical 62-passenger Sea Lion and Sea Bird, includes 7-night cruises between Juneau and Sitka from May to August, and an 11-night cruise between Seattle and Juneau (including the San Juan Islands and British Columbia) in April and September.

Passenger Profile -- Lindblad Expeditions tends to attract well-traveled and well-educated, professional, 55-and-older couples who have "been there, done that" and are looking for something completely different in a cruise experience -- and who share a belief in the need to preserve the environment.

Ships -- The 62-passenger National Geographic Sea Lion and National Geographic Sea Bird (built in 1981 and 1982, respectively) are nearly identical. Both are well-appointed vessels built to get you to beautiful spots and feature a minimum of public rooms and conveniences: one dining room, one bar/lounge, and lots of deck space for wildlife and glacier viewing. They have the added advantage of being accompanied throughout by historians, anthropologists, scientists, and other such specialist lecturers chosen by the National Geographic Society. Cabins are small and functional, but not inexpensive. Sample nightly rates per person: Lowest-price outside cabin $748 for 7-night cruises; no inside cabins or suites.